Page 14 - HVAC Pump Handbook

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Digital Electronics and HVAC Pumps

Digital Electronics and HVAC Pumps 11

coming to an end, giving way to the variable-speed pump, which can
adjust more easily to system conditions with much less energy and
smaller forces on the pump itself. Along with the constant-speed
pump go the mechanical devices described earlier that overcame the
excess pressures and flows of that constant-speed pump. The vari-
able-frequency drive with electronic speed control and pump pro-
gramming matches the flow and head developed by pumps to the flow
and head required by the water system without mechanical devices
such as balance valves.

1.12 Electronic Commissioning

Another great asset of electronics applied to water systems is its use
during the commissioning process. There are always changes in draw-
ings and equipment during the final stage of starting and operating a
water system for the first time. Many of these changes in equipment
and software can be recorded easily through the use of portable com-
puters or other handheld electronics. The agony of ensuring that “as-
built” drawings are correct has been reduced greatly.
Electronic instrumentation and recording devices have accelerated
the commissioning of water systems. Verification of compliance of the
equipment of a water system is enhanced by these instruments.

1.13 Purpose of This Book
It is one of the basic purposes of this book to describe in detail all the
preceding uses of electronics in the design and application of pumps
to HVAC water systems. This must be done with recognition that the
rapid development of new software and equipment is liable to rele-
gate any description of digital electronics to obsolescence at the time
of writing. The development of online data services is going to change
even further the way we design these water systems.
The HVAC design engineers must understand where their offices
are in the use of available electronic equipment and services; this en-
sures that they are providing current system design at a minimum
cost to their company. The engineers who do not use electronic equip-
ment, network the office, or subscribe to online data services as they
come available will not be able to keep up with his or her contempo-
raries in design accuracy and speed.
One of the reasons for the writing of this book was to produce a
handbook for HVAC pumps that would provide basic design and ap-
plication data and embrace the many and rapid changes that have oc-
curred in water system design and operation. This Handbook has
been written to guide the student and inexperienced designer and, at

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